The present invention relates to pulls stud bolts, which are used in, for example, metal-working machinery.
Pull studs and pull stud bolts are disclosed in U.S. Pat. Nos. 5,946,789; 5,885,039; 5,846,037; 5,823,722; 5,762,454; 5,735,651; 5,700,115; 5,690,137; 5,662,422; 5,660,510; 5,640,749; 5,639,194; 5,623,730; 5,593,258; 5,539,970; 5,538,379; 5,407,308; 4,977,799; 4,541,533; and others.
Conventional pull stud bolts comprise a male screw portion toward one end, a grip porion toward the other end and a flange portion formed between the two portions. The flange portion has a pair of wrench engaging faces.
When the pull stud bolt is to be tightened up on a shank or loosened from the shank, a wrench is first fitted to the wrench engaging faces of the stud bolt with its handle down. The wrench is then turned through 180 deg to position the handle up. The wrench is thereafter released from the wrench engaging faces. The pull stud bolt is tightened up on the stud bolt or loosened by repeating this procedure.
Thus, the conventional pull stud bolt must be handled by turning the wrench through 180 deg and therefore has the problem of necessitating turning of the wrench through a large angle, for example, for tightening up the stud bolt, hence difficult work.
An object of the present invention is to provide a pull stud bolt which can be handled easily by turning a wrench through a reduced angle, for example, for tightening up.
The present invention provides a pull stud bolt which comprises a flange having two pairs of wrench engaging faces, the adjacent wrench engaging faces making an angle of 90 deg with each other.
The pull stud bolt has a flange provided with two pairs of wrench engaging faces, and the adjacent wrench engaging faces make an angle of 90 deg with each other, so that for example when the pull stud bolt is tightened up by repeating the sequential actions of rotating the stud bolt by a wrench, then removing the wrench from the flange and engaging the wrench with the flange again, the wrench is turned through 90 deg at a time.
The present invention provides another pull stud bolt which comprises a flange having three pairs of wrench engaging faces, the adjacent wrench engaging faces making an angle of 120 deg with each other.
In the case of this pull stud bolt, the wrench is turned through 60 deg at a time, for example, when the pull stud bolt is tightened up by repeating the sequential actions of releasing the wrench from the flange and engaging the wrench with the flange again.
Thus, the pull stud bolt of the present invention assures easy work since the stud bolt can be handled by turning the wrench through one-half or one-third the angle conventionally needed.